The transmission or recording of conventionally encoded color television signals (either NTSC (US) or PAL (European)) is complicated by the fact that encoded color information is contained in a high frequency subcarrier that is close to the upper limit of the spectrum of video frequencies. As a consequence, particular care must be taken to ensure that the transfer process (i.e., transmission or recording) does not introduce frequency fluctuations or distortions in amplitude and phase characteristics of the encoded video signal. This has been a well recognized problem, and various attempts have heretofore been made to solve, or at least minimize, the problem, usually by some type, or process, of re-encoding the signal.
While it is now known that overall bandwidth may be conserved by a technique in which each individual line of video information is first recorded in some type of memory and then read out at a reduced rate to produce a "slow-scan" television signal, this technique does not solve the problem set forth hereinabove. In addition, while some "slow-scan" systems have heretofore employed orthogonal transformation techniques for generating slow-scan TV signals (see, for example, U.S. Pat. Nos. 3,284,567 and 3,683,111), such techniques have not heretofore been utilized to produce a completely effective and ecconomical means of re-encoding a conventional color TV signal for transmission or recording purposes, and refinements thereof were therefore felt to be useful.